Composting Toilets - approach to sustainability

In achieving sustainability, considerations can be placed into looking into transportation, materials, and natural systems. When considering transportation, one approach is for more ‘stalls’ to be transported in one trip compared to the transportation of conventional portable washrooms, another approach is to carry the same amount of ‘stalls’ but consuming less energy due to lighter loads. Another approach to sustainability can be through the materials chosen to construct the final structure, using sustainably sourced natural materials that can re-enter the system as a new ‘technical ingredient’. Finally, we can consider the natural system of waste management to manage our waste as nutrients for our ecosystems. With the increase of pollution, declining water tables, prolonged drought conditions, shrinking usable water supply, and an increasing demand of water resource, water is a resource that is dwindling. This means abuse on the quantity and quality of water is unsustainable, and requires more time and resources to treat the water back into an acceptable state for public use (Government of Canada 2009).

Current waste from portable washrooms and a non-formaldehyde concentration liquid used in the units, are being dumped back into our waste water management system and would affect the water quality. Current waste water system takes our waste and treats it to allow for biosolids application. However, our waste can be made directly into fertilizer directly through an optimized and accelerated process of decomposition and evaporation. Companies such as Sun-Mar, has designed dry toilets that embraces the natural process of decomposition. In this way our waste would not have to enter our municipal wastewater system and would avoid contaminating our water source.

However, adopting such a system introduces interesting questions to consider,

Since not many users currently understand how to properly handle a dry toilet, would maintenance staff be required to properly care for these units?

As time is required for composting to occur, is this process an appropriate solution to be applied to a festival setting, where it would be used for a shorter period of time?

As traffic through washroom facilities are greater than personal home use, would the drum of the composting toilet be able to handle the higher amounts of waste?

Another efficient process is to use zinc oxide nanorods grown on an optical disk that would function as a photocatalyst and break apart pollutants in sewage when illuminated with ultraviolet light. This process speeds up the degradation process and can treat 150ml of waste water per minute. (Optical Society of America 2013)